The invention relates to a self-deploying axial-flow pump to be introduced intravascularly for temporary cardiac support.
In a cardiogenic shock, the ejection rate of the left ventricle is substantially reduced. The lowered supply to the heart can lead to irreversible heart failure. A temporary support system for the left ventricle is used to take over a part of or the entire pump function of the left ventricle and to improve the coronary perfusion. In cardiac surgery, such a system can be used for the left and the right ventricle and may replace a heart-lung machine.
A system for percutaneous implantation that has gained some clinical importance, is the intra-aortal balloon counter-pulsation (IABP). However, the haemodynamic improvement achievable is rather limited.
After experimental and preliminary clinical tests, a known axial-flow pump xe2x80x9cHemopump(trademark)xe2x80x9d for transfemoral implantation appears to be a promising concept that might achieve a sufficient relief of the left ventricle. The intake stud of the pump is placed retrogradely above the aorta valve in the left ventricle. The pump rotor is located at the end of a cannula in the upper aorta descendens and is driven by an external motor. It is a disadvantage of this system that, due to the large diameter of the motor, the transfemoral implantation is possible only surgically through a femoral arteriotomy and, eventually, a graft coupling.
It is the object of the present invention to provide a transfemorally insertable axial-flow blood pump for cardiac support that may be introduced intravascularly without an operation.
The radial compressibility of the elements allows to realize a small puncture diameter acceptable for a percutaneous implantation following the Seldinger technique. By deploying the device in the cardiovascular system, a relatively large pump diameter of 10 to 14 mm can be provided. Thereby, the rotor speed, and thus the mechanical stress on the elements, is lowered.
The following is a detailed description of an embodiment of the invention, given with reference to the drawings.